The present invention concerns the making of dental impressions for use in making crowns, caps, bridges, etc.,.
The quality of the above dental items is largely determined by the precise nature of a dental impression taken of the patient's teeth. Impression material is typically deposited into an impression tray whereafter the loaded tray is manually biased upwardly or downwardly for intimate contact with the upper or lower teeth and gums. The impression tray must be carefully applied and removed to avoid subsequent displacement of the impression material and resulting inaccuracy. The displacement procedure currently used hinders the forming of optimum impressions as voids and other inaccuracies caused by saliva, blood and trapped air may occur in the viscous material. The resulting crowns, caps, bridges, etc., hence require considerable corrective effort to re-shape the item or article being constructed. Accordingly, imperfect impressions jeopardize the quality of the finished piece as well as adversely affect their cost by reason of excessive reworking of the finished article.
In wide use in the dental field are impression trays comprising an outer wall and an inner wall which serve to confine impression material deposited in place on a bottom or interconnecting wall of the tray. The tray is provided with an extension for purposes of manipulation of the tray during taking of the impression.